Hi John

I’m not sure if this helps…

I am also sure you can get the cluster running with half the nodes.

I am actually migrating between two HA-pairs as we speak.

We choose to setup a link between the nodes with two cluster switches, so the two HA-pairs is about 500M apart… (I’m not sure when latency becomes an issue)

But what we did was to add the two new nodes (temporary nodes) to the existing cluster, and we are then able to use the “vol move” operation to move volumes from one HA-pair to another, and of cause also the LIFs.

Works a charm so far.  Huge NFS datastores have been moved with a hitch.

We did a “vol move start” with the “-cutover-action wait” option, which does the mirroring but waits until we tell it to do the cut-over… (in a service window)

There is however some “dedupe processes” which makes the cut-over very slow on larger volumes… it keeps telling us that it is waiting for a dedupe process to complete… (both systems are AFFs)…. But after 10-30 minutes it completes OK.

Once we have emptied the source HA-nodes, we will move them to the new DC, and do it all over again back to the original system again…

So far no down time at all, which is nice 😊

I realize that you may not be a lucky as to where you have to move the systems 😉

So drive safely, and if you are running spinning disks, be prepared to replace a few as you startup the system 😉

/Heino

Fra: Toasters <toasters-bounces@teaparty.net> på vegne af John Stoffel <john@stoffel.org>
Dato: tirsdag, 2. marts 2021 kl. 19.24
Til: toasters@teaparty.net <toasters@teaparty.net>
Emne: Moving a 4 node cluster in two pairs?

Guys,
We're getting ready to move our 4 node FAS8060 cluster to a new data
center.  As part of our due diligence, we're thinking that we would
snapmirror the most critical business volumes between the two pairs.

The idea would be that if the truck holding pair A+B doesn't make it
for some reason, we can still bring up the cluster with nodes C+D and
still have those snapmirrored volumes available to continue working.

So my questions are:

1. Can I boot a cluster with half the nodes missing?  I'm sure I
   can...

2. Has anyone else had to do this half assed method of shipping DR?

Cheers,
John
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